1. Field of the Invention
The present invention relates to a cushion mounting structure of a saddle-ride vehicle, and more particularly to a cushion mounting structure of a saddle-ride vehicle which is favorable to a three-wheeled vehicle or a four-wheeled vehicle which travels on a terrain.
2. Description of Background Art
Conventionally, as a rear wheel suspension structure in a saddle-ride vehicle which travels on a terrain, there has been known a double-wishbone-type independent suspension structure in which wheels are supported by suspension arms constituted of upper and lower arms. (For example, see JP-A-2003-56607.) Further, in the rear wheel suspension structure described in JP-A-2003-56607, an impact which left and right wheels receive is absorbed by a pair of cushion units which connects an upper end thereof to a vehicle body frame and a lower end thereof to a suspension arm and, at the same time, is arranged vertically with respect to a vehicle body in a side view, and is arranged in a chevron shape with respect to a vehicle body in a front view.
Here, in JP-A-2003-56607, although a stroke length which allows the mounting of the cushion unit obliquely in the vehicle body width direction is ensured, the elongation of the stroke length is limited due to the limitation imposed on a vehicle height and a vehicle width. Accordingly, there has been a demand for the acquisition of a favorable cushion performance by elongating the stroke length of the cushion unit.
Further, with respect to a motorcycle which includes a cushion unit for absorbing an impact on wheels, there has been known a motorcycle in which a link member which is tiltably arranged parallel to an arm member which supports a rear wheel is provided, the cushion unit is connected to an arm member by way of a link member thus ensuring a stroke length of the cushion unit in a narrow space and the acquisition of a favorable cushion performance in conformity with the tilting direction of the link member and the arm member. (See JP-A-57-60984, for example.)
Further, with respect to the motorcycle described in JP-A-57-60984, although the motorcycle possesses the favorable cushion performance with the use of the link member, the saddle-ride type vehicle which extends the suspension arm in the vehicle body width direction is also requested to acquire such favorable cushion performance with the use of the link member.
In addition, a saddle-ride type vehicle which travels on a terrain includes a vehicle body frame which is assembled by welding pipe-like frame members, wherein wheels are supported on the vehicle body frame by way of suspension arms.
Recently, to realize the easiness of assembling and the reduction of weight by the simplification of the structure, a so-called bolt-on type frame which is assembled by fastening and fixing a pair of divided frames which are split into left and right frames using bolts and nuts is adopted. (See JP-A-1-109186, for example.)
Here, in the frame structure disclosed in JP-A-1-109186, bulging portions in which hole portions for allowing bolts to pass therethrough are formed on outer peripheral sides of the divided frames, and these bulging portions are fastened and fixed to each other using bolts and nuts thus integrally forming the divided frames. Accordingly, there has been a drawback that an appearance of the vehicle is damaged by the bulging portions.